678 research outputs found

    Thermal control of space vehicles Patent

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    Passive thermal control coating on aluminum foil laminate for inflatable spacecraft surface

    Random harmonic analysis program, L221 (TEV156). Volume 2: Supplemental system design and maintenenace document

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    Volume 2 of a two volume document is presented. A computer program, L222 (TEV 156), available for execution on the CDC 6600 computer is described. The program is capable of calculating steady-state solutions for linear second-order differential equations due to sinusoidal forcing functions. From this, steady-state solutions, generalized coordinates, and load frequency responses may be determined. Statistical characteristics of loads for the forcing function spectral shape may also be calculated using random harmonic analysis techniques. The particular field of application of the program is the analysis of airplane response and loads due to continuous random air turbulence

    Local initiation of spermatogenesis in the horse

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    Gross observation of testicular parenchyma of 1.5 to 2-yr-old horses reveals both light and dark regions. If this gross, differential shading reflects quantitative differences in the development of spermatogenesis and interstitial cell populations, the horse may prove to be a useful model for study of the paracrine relationships associated with initiation of spermatogenesis. The objective of this study was to characterize seminiferous tubules and interstitium of testes with gross, differential shading. Testes with both light and dark regions of parenchyma were obtained from horses 1.5- 2 yr old and compared to parenchyma of fetal, 2-yr old, or 5-yr-old horses. Stereology was used on tubular and interstitial components, and luminal development of seminiferous tubules was scored. Volume density of seminiferous tubules, percentage of tubules with large vacuoles or a complete lumen, and number of primary spermatocytes per gram were greater (p \u3c 0.05) in light parenchyma than in dark parenchyma. The percentage of tubules with no lumen and the percentage of parenchyma occupied by interstitial space were greater (p \u3c 0.05) in fetal and dark parenchyma than in light parenchyma. The number of Leydig cells per gram parenchyma was similar (p \u3e 0.05) in both light parenchyma and dark parenchyma. A greater percentage (p \u3c 0.05) of other (nonvascular, non-Leydig, nonmacrophage) cells was found in the dark parenchyma than in light parenchyma or in testes of 2- or 5-yr-old horses. The volume density of macrophages was notably greater (p \u3c 005) in fetal and dark parenchyma than in light parenchyma or in testes from older horses. Variation in development of seminiferous tubules was not associated with the volume density of blood vessels. In conclusion, the gross, differential shading of equine testicular parenchyma with its corresponding differences in seminiferous tubular development is a clear example of tile effect of local factors leading to the local initiation of spermatogenesis

    Electromagnetic waves and bursty electron acceleration: implications from Freja

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    International audienceDispersive Alfvén wave activity is identified in four dayside auroral oval events measured by the Freja satellite. The events are characterized by ion injection, bursty electron precipitation below about 1 keV, transverse ion heating and broadband extremely low frequency (ELF) emissions below the lower hybrid cutoff frequency (a few kHz). Large-scale density depletions/cavities, as determined by the Langmuir probe measurements, and strong electrostatic emissions are often observed simultaneously. A correlation study has been carried out between the E and B field fluctuations below 64 Hz and 10 Hz, respectively, (the DC instruments upper threshold) and the characteristics of the precipitating electrons. This study revealed that the energisation of electrons is indeed related to the broadband ELF emissions and that the electrostatic component plays a predominant role during very active magnetospheric conditions. Furthermore, the effect of the ELF electromagnetic emissions on the larger scale field-aligned current systems has been investigated, and it is found that such an effect cannot be detected. Instead, the Alfvénic activity creates a local region of field-aligned currents. It is suggested that dispersive Alfvén waves set up these local field-aligned current regions and, in turn, trigger more electrostatic emissions during certain conditions. In these regions, ions are transversely heated, and large-scale density depletions/cavities may be created during especially active periods

    The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) Mission

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    The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) CubeSat mission is a NASA funded HTIDs project. It is a 3-year grant with two 1.5U CubeSats with an estimated delivery in the spring of 2020 and a 1- year on-orbit mission life. Each CubeSat will host a miniature ionization gauge space instrument (MIGSI), planar ion probe (PIP), and GPS radio occultation sensor (CTECS-A). The mission is to provide both ionosphere and thermosphere measurements related to the Equatorial Ionization Anomaly (EIA) and the Equatorial Temperature and Wind Anomaly (ETWA). The EIA and ETWA are two of the dominant ionosphere/thermosphere interactions on the low-latitude duskside. While the EIA has been extensively studied both observationally and with modeling, the ETWA is less well known since observations are infrequent due to a lack of suitably instrumented spacecraft (s/c) at appropriate altitudes. LLITED will, for the first time, provide coincident high-resolution measurements of the duskside ionosphere/thermosphere at lower altitudes that will characterize and improve our understanding of the ETWA, provide insight into the coupling physics between the ETWA and EIA, and increase our knowledge of the duskside dynamics that may influence space weather. The following paper reviews the science mission and concepts and then provides the current status of the LLITED hardware

    Guidance for the treatment of adult growth hormone deficiency with somapacitan, a long-acting growth hormone preparation

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    Adult growth hormone deficiency (AGHD) is a rare endocrine disorder characterized by an abnormal body composition, metabolic abnormalities associated with increased cardiovascular diseases, bone loss, and impaired quality of life. Daily subcutaneous injections with recombinant growth hormone (GH) can alleviate the abnormalities associated with AGHD. Several long-acting GH (LAGH) preparations are currently in development that aim to reduce treatment burden for patients receiving daily GH injections. Somapacitan (Sogroya®; Novo Nordisk, Denmark) is the first LAGH preparation that has been approved for treatment of AGHD in the United States, Europe, and Japan. The recent approval of somapacitan and anticipated approval of other LAGH molecules presents new questions for physicians planning to treat AGHD with LAGH in the future. Differences in the technologies used to prolong the half-life of recombinant GH are expected to result in variations in pharmacokinetic and pharmacodynamic profiles between preparations. Therefore, it is essential that physicians understand and consider such variations when treating patients with these novel GH replacement therapies. Here, we present a set of treatment recommendations that have been created to guide physicians initiating therapy with somapacitan in patients with AGHD who are eligible for GH replacement. Furthermore, we will review the published data that underlie these recommendations to explain the rationale for the treatment and monitoring advice provided

    Dietary components that regulate serum somatomedin-C concentrations in humans.

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    Dietary components responsible for the regulation of somatomedin-C in humans were assessed in five adult volunteers of normal weight who were fasted for 5 d on three occasions, then refed three diets of differing composition. The serum somatomedin-C decreased from a mean prefasting value of 1.85 +/- 0.39 U/ml (+/- 1 SD) to 0.67 +/- 0.16 U/ml at the end of fasting (P less than 0.005). After refeeding for 5 d with a normal diet, the mean serum somatomedin-C increased to 1.26 +/- 0.20 U/ml. A protein-deficient (32% of control), isocaloric diet resulted in a significantly smaller increase, to a mean value of 0.90 +/- 0.24 U/ml (P less than 0.05). A diet deficient in both protein and energy led to a further fall 0.31 +/- 0.06 U/ml. The changes in somatomedin-C during fasting and refeeding correlated significantly with mean daily nitrogen balance (r = 0.90). We conclude that both protein and energy intake are regulators of serum somatomedin-C concentrations in adult humans, and energy intake may be of greater importance. The correlation between changes in somatomedin-C and nitrogen balance suggests that the former are directly related to changes in protein synthesis and may be helpful in assessing the response to nutritional therapy

    Airglow Emissions and Oxygen Mixing Ratios from the Photometer Experiment on the Turbulent Oxygen Mixing Experiment (TOMEX)

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    The Turbulent Oxygen Mixing Experiment (TOMEX) combined Na lidar measurements from Starfire Optical Range in Albuquerque, New Mexico, with a launch of a payload from White Sands Missile Range (WSMR), located a little over 100 km from Starfire. The payload included a trmethyl aluminum release to measure winds and diffusion, a 5-channel ionization gauge to measure neutral densities, and a 3-channel photometer experiment to measure atomic oxygen related airglow. The payload was launched at 0957 UT on 26 October 2000 and successfully obtained data from all the experiments. The photometer experiment consisted of three liquid nitrogen cooled filter photometers which measured emission from the O2 atmospheric band (0, 0) emission, the OH Meinel (9, 4) band, and the OI(557.7 nm) greenline. Measurements were made as the rocket went from 80 to 110 km on the upleg. The pointing of the photometers was within a few degrees of zenith. Differentiating these data allowed volume emission rates to be derived which can be inverted to form atomic oxygen density profiles. The interpretation of the data made use of simultaneous atmospheric temperature data from the Na lidar. The airglow data showed lower brightness values and lower peak altitudes for the O2 atmospheric (0, 0) band and OI(557.7 nm) emissions than predicted by the thermosphere/ ionosphere/mesopshere/electrodynamics general circulation (TIME-GCM) model. The peak altitude of the OH Meinel emission seemed nominal. Inverting the O2 atmospheric (0, 0) and OI(557.7 nm) data following McDade et al. [1986] produced O density profiles whose peak densities and peak altitudes are lower than the model values. The shape of the O density profile is also more constant with altitude than model predictions. The O mixing ratio shows a more altitude-independent profile than given by the model, especially between 85 and 95 km. Significant deviations in the measured shape of the mixing ratio also occur at 90, 97, and 102 km. The interpretation of these data is that the O mixing ratio was significantly perturbed by the passage of an atmospheric gravity wave or tide and the subsequent convective or dynamical instabilities produced by that wave. Dynamically or convectively unstable layers at 90, 97, and 102 km at the time of the launch also appear to be reflected in the mixing ratio data
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